The wireless control system, LimeLight, from TwistHDM6 in Holland, MI, was originally launched for a fluorescent parking garage fixture, but TwistHDM expressed an interest in using this project to demo their control system with an LED fixture.

Ultimately, two of the three underground floors at Fourth and Washington were converted to LED (28 fixtures total) and TwistHDM donated fluorescent fixtures for the third floor. To take full advantage of this unique opportunity to have three different lighting technologies in one parking structure (the existing metal halide fixtures, LimeLight‐controlled fluorescent fixtures, and LimeLight‐controlled LED fixtures), sub‐meters were installed to measure actual energy use from one floor of each fixture type. Another manufacturer of LED fixtures has since donated fixtures to retrofit one of the above‐ground floors for another comparison, although that floor is not being sub‐metered.

Sub‐metering is important to compare the actual energy use of lighting that is on control systems, as with these LimeLight‐controlled fixtures, as duty cycle of the fixtures will vary depending on control settings and traffic into and out of the garage. The installation was completed in November 2010 and a full evaluation of the energy use data will be conducted in Summer 2011 to help the DDA make a decision on lighting for the new underground parking structure, which is under construction as of this writing (May 2011).